Less Prevnar May Be Just As Good. Don’t Expect Changes Soon.

What’s the right amount of the childhood vaccine Prevnar? A study published in JAMA today suggests that three doses may be as effective as the four doses that are standard in the U.S. and many other countries.

Private insurers pay $83 per dose for Prevnar in the U.S., so the cost of that fourth dose adds up. It’s the best-selling vaccine in the world and generated $2.7 billion …